Dual pressure range valve

ABSTRACT

Dual pressure range valve for alternately providing high pressure and low pressure fluid over a single line, the valve including a body having a high pressure fluid inlet port and a low pressure fluid inlet port, both the inlet ports being alternately communicable with a fluid outlet port. Communication of the fluid outlet port with the high pressure or low pressure fluid inlet port is established by the positioning of reciprocable means mounted within the valve body.

United States Patent lnventor Duane L. Kirschenman [56] References CitedWinston-Salem, N.C. UNITED STATES PATENTS Appl 796,344 2,716,997 9/1955Crookston 187/102 PM 1969 2,816,563 12/1957 Pappas 137/102 patimed 19713,151,624 10/1964 Kootnik.. 137/112 Asslgnee Western Elem (bmpany, 3 454029 7/1969 Fredd 137/1 1 1 New York, N.Y. 1

Primary ExaminerWilliam F. ODea Assistant Examiner-William H. WrightAttorneys-H. J. Winegar, R. P. Miller and S. Gundersen P PRESSURE MVALVE ABSTRACT: Dual pressure range valve for alternately provid- 1Claim, 6 Drawing Flgsing high pressure and low pressure fluid over asingle line, the US. Cl 137/113, valve including a body having a highpressure fluid inlet port 91/32, 137/1 12 and a low pressure fluid inletport, both the inlet ports being Int. Cl 605d 16/04 altematelycommunicable with a fluid outlet port. Communi- Field of Search 121/150;Cation of the fluid outlet port with the high pressure or low 137/108,102, 113, 111, 1 12; 303/71 (310), 4-6; pressure fluid inlet port isestablished by the positioning of 91/31, 32 (X) reciprocable meansmounted within the valve body.

is 55 56 66 54 65 68 x 34 5o 58 4 7 7 v %6/ 9 52 I 76 6'3 4 DUALPRESSURE RANGE VALVE BACKGROUND OF THE INVENTION It is often anoperational requirement of various types of machinery that componentsthereof be moved, not under load, for relatively long distances andthereafter be moved, under load, for relatively long distances andthereafter be moved, under load, for relatively short distances. Typicalof such machinery is a punch press for forming holes in a blank ofmaterial. Such a press ordinarily operates subject to a cycle whichincludes the steps of advancing a ram from a remote position to apunching position, accomplishing the punching operation, and retractingthe ram to the remote position to facilitate removal of the punchedblank and insertion of an unpunched blank for the next punching cycle.The advancing and retracting steps require the unloaded ram to bedisplaced relatively long distances under a relatively light load,whereas the punching step requires that the ram be displaced arelatively short distance, but under a relatively heavy load.

Conventional apparatus for powering such low load long distance and highload-short distance travel of machine components ordinarily comprisehydraulic systems which provide a high volume of low pressure fluid andlow volume of high pressure fluid to the machinery being served. In someapparatus the high pressure and low pressure fluids are introduced tothe served machinery through separate fluid systems. Other apparatusintroduce a high volume of high pressure fluid to the served apparatus,whereafter the pressure of a great portion of the fluid is reduced forproviding the necessary high volume of low pressure fluid.

The former approach, i.e. separately introduced high and low pressurefluids, has been found to be undesirable since the served machinery mustbe structured to accommodate each of the separately introduced high andlow pressure fluids. The latter approach, ie the introduction of a largevolume of high pressure fluid, also has been found to be undesirable inthat the provision of such a large volume of high pressure fluid isfundamentally ineflicient and difficult to accommodate, and thesubsequent pressure reduction requires complex apparatus. Accordingly,those skilled in the art have directed their attention to providingfluid, at high or low pressures as required, to machinery being servedthrough a single source line.

The provision of fluid, at high or low pressures from separate pressuresources to a common fluid line requires, at some point in the system, avalve which is capable of controlling the flow of fluid from theseparate pressure source to the common fluid line in accordance with theneeds dictated by the operating requirements of the machine to beserved.

The present invention embodies such a valve.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS A morecomplete understanding of the dual pressure range valve of the presentinvention may be had from the following detailed description thereof,particularly when considered in the light of the attached drawingswherein:

FIGS. 1a, b and c are schematic views of the operation of ahydraulically operated press ram, fluid for the operation of which isprovided through a dual pressure range valve according to the presentinvention;

FIG. 2 is a cross-sectional, elevational view of a dual pressure rangevalve according to the present invention, the valve elements being shownin alignment for low pressure fluid flow;

FIG. 3 is a cross-sectional, elevational view similar to that of FIG. 2,but showing the valve elements in alignment for high pressure fluidflow; and

FIG. 4 is a cross-sectional, elevational view similar to that of FIG. 2,but of an alternate embodiment of a dual pressure range valve structuredin accordance with the teaching of the present invention.

DETAILED DESCRIPTION The dual pressure range valve of the presentinvention may be used in any hydraulic system wherein high pressurefluid from one source and low pressure fluid from a second source mustbe provided alternately through a single fluid line, Many hydraulicallyoperated machines have such a requirement, typical of such machinesbeing punch presses which are used for punching holes in metal blanks.Accordingly. the dual pressure range valve of the present invention willbe described below in use with such a machine for purposes ofillustration, it being recognized that the valve may be used with manyother machines having similar hydraulic fluid requirements.

Referring therefore to FIG. I la, a dual pressure range valve,designated generally by the reference numeral I0, is shown in use with aconventional punch press designated generally by the reference numeralII. The punch press II is provided with a punching ram 12 having apiston I4 mounted on one end thereof, the piston 14 being reciprocablyreceived in a fluid pressure cylinder 15. The lower surface of punch ram12 serves as a punch for punching a circular disc I6, FIG. lb, from ablank plate 17. The punching of disc l6-is accomplished through asuitable opening I8formed in a die plate I9 which also serves to supportthe blank I7.

Dual pressure range valve 10 is in fluid communication with vessel I5through a connecting fluid line 21 which extends from an outlet port ofvalve I0, as will be described in detail below, to the chamber of thevessel I5 which is above piston 14 as seen in FIG. 1. Thus, fluid passedthrough line 21 into vessel I5 will tend to displace piston I4, andtherewith punch ram 12, downwardly. Valve 10 is also connected to a highpressure fluid line 22 which leads from a source of high pressure fluid(not shown), and a low pressure fluid line 23 which leads from a sourceof low pressure fluid (not shown).

In FIG. la, punch ram I2 is shown in a retracted position forfacilitating the positioning of a blank 17 on die plate I9 prior topunching. Once the blank 17 is suitably positioned, a high volume of lowpressure fluid is admitted through fluid line 23,

' valve 10 and connecting line 21 to vessel I5 above piston I4 so as torapidly advance punch ram 12 through distance x to a position ofsurface-to-surface contact with blank I7. The punch ram '12 advancesonly to this surface-to-surface contact position since the pressureavailable in the low pressure fluid system, while adequate for rapidlydisplacing and positioning the punch ram when not under load, is notsufficient to accomplish the punching operation.

Punching, as shown inFIG. Ib, is accomplished by introducing a smallvolume of high pressure fluid from high pressure fluid line 22 throughvalve 10 and connecting line 2i into vessel 15 above piston I4. Thepressure of the fluid from line 22 introduced into vessel 15 issufficient to generate the required force to punch the disc I6 fromblank I7. and the volume of high pressure fluid supplied is sufficientto displace ram I2 through a distance y to both punch and clear disc I6through opening 18 in die plate 19.

After punching is completed, punch ram 12 is retracted FIG. 1c, tofacilitate removal of the punched blank. Retraction is accomplished bythe introduction of low pressure fluid through a low pressure fluid line24 which communicates with vessel I5 below piston 14. Fluid pressureabove piston I4 in vessel 15 is relieved by relieving the pressures inboth the high pressure fluid line 22 and the low pressure fluid line 23thereby allowing the piston 14 and therewith punch ram I2 to bedisplaced upwardly within vessel 15 through the distance z as shown inFIG. Ic. At this stage, punch press II is in position to repeat thepunching cycle.

Clearly, therefore, a machine such as punch press 11 is a prime exampleof hydraulic equipment with which the dual pressure range valve of thepresent invention is particularly useful. One embodiment of such a valveis shown in FIGS. 2 and Brand designated generally by the referencenumeral 30. Valve is shown in FIG. 2 with its components aligned forpassing a high volume of low pressure fluid therethrough.

Dual pressure range valve 3% comprises a body 32 having a bore 34extending longitudinally axially therethrough. One end of bore 34, theupper end as seen in FIG. 2, is provided with a threaded counterbore 36for receiving a high pressure connector plug 37. Connector plug 37 isprovided with an axially extending bore to define a first inlet port 38through which high pressure fluid is introduced to valve 30 from asuitable source (not shown). The other end of bore 34, the lower end asseen in FIG. 2, is provided with a threaded counterbore 40 which is forthreadedly receiving a connector 41. Connector 41 is provided with alongitudinally axially extending bore to define an outlet port 42 foraccommodating the passage of high or low pressure fluids from valve 30.Connector 41 may be secured directly to the inlet orifice 43 of amachine 44 to be served, e.g. the punch press 11 of FIG. 1, or it may besecured to a suitable high pressure fluid line (not shown).

A pair of axially spaced, radially inwardly extending annular shoulders47, 48 are formed on the inner surface of bore 34. Shoulders 47, 48cooperate to define a central bore portion 50 from which a passage 52extends radially through valve body 32. The outer end of passage 52defines a second inlet port 53 (FIG. 3) to valve 30, and is providedwith threads for accommodating the connection thereto of a suitablesource of a high volume of low pressure fluid (not shown).

Slidably mounted within bore 34 is a check piston 54 having a bore 55extending longitudinally axially therethrough. Axially slidably receivedwithin bore 55 is a check stem 56, the diameter of which is slightlysmaller than the diameter of bore 55 so as to allow the free flow offluid therebetween. The lower end of check stem 56 (as seen in FIG. 2)is provided with a flared plug 57 having an upper conical surface 58, alower conical surface 59, a flat bottom surface 60 and a plurality ofpassages 63 extending therethrough from upper conical surface 58 to flatbottom surface 60. When valve 30 is aligned for low pressure, highvolume flow, as shown, upper conical surface 58 is engageable with acomplementary tapered surface 61 formed in the lower end of bore 55thereby closing passages 63 so as to preclude the flow of fluid upwardlythrough bore 55. When valve 30 is aligned for high pressure, low volumeflow, as shown in FIG. 3, the lower conical surface 59 of plug 57 isengageable with a complementary tapered surface 62 formed in the upperend of port 42 in threaded connector 41 thereby opening passages 63 soas to allow the flow of high pressure fluid downwardly through bore 55.Thus, check stem 56 with its associated plug 57 cooperates with taperedsurface 61 of check piston 54-to define a stem check valve in checkpiston 54 for permitting the flow of fluid from the inlet port 38 tooutlet port 42 during high pressure, low volume operation, whileprecluding a reverse flow of fluid from outlet port 42 to inlet port 38during low pressure, high volume operation. Formed adjacent the upperend of check piston 54 is a radially outwardly extending shoulder 64.The diameter of shoulder 64 is substantially equal to the diameter ofbore 34 so as to provide a surface-to-surface sliding fit therebetween.The chamber 66 defined by the outer surface of check piston 54, bore 34,the lower surface of shoulder 64 and the upper surface of shoulder 47 isvented to the atmosphere through a suitable passage 65 which extendsradially outwardly through valve body 32 from a point just aboveshoulder 47. Such venting is provided to preclude a build up in pressurebelow shoulder 64, which build up would otherwise tend to retard thedisplacement of check piston 54 from low pressure, high volume alignment(FIG. 2), to high pressure, low volume alignment (FIG. 3).

As was noted above, check piston 54 is slidably mounted in bore 34 andis reciprocable between an upper position (FIG.

2) for accommodating high volume, low pressure fluid flow, and a lowerposition (FIG. 3) for accommodating low volume, high pressure fluidflow. Referring to FIG. 3, therefore, it can be seen that check piston54 has been moved downwardly within bore 34 such that the lower surfaceof shoulder 64 of check piston 54 is in abutting engagement with theupper surface of shoulder 47 of bore 34. Additionally, stem 56 is shownas having moved downwardly within bore 55 of check piston 54 so that thelower conical surface 59 of plug 57 is in engagement with the taperedsurface 62 of bore 42 in threaded connector 41. With the stem 56 andplug 57 in this position, passages 63 in plug 57 are uncovered so as toallow the free passage of fluid therethrough from bore 55 of checkpiston 54 to bore 42 of connector pipe 41.

The leakage of fluid from the desired fluid flow paths within valve 30during the operation thereof is prevented by the provision of a seriesof seals mounted within the valve structure, some of which are operativeduring both high and low pressure operation of the'valve. and some ofwhich arc-operative only during high pressure operative of the valve.

Considering initially the alignment of elements and sealing arrangementfor accommodating a low pressure, high volume flow of fluid (FIG. 2),check piston 54 is in its uppermost position so as to be insurface-to-surface contact with the lower surface of connector plug 37.Check stem 56 is also in its uppermost position such that the upperconical surface 58 of flared plug 57 is in surface-to-surface engagementwith the complementarily tapered surface 61 on the lower end of bore 55of check piston 54. With check stem 56 in this position, it can be seenthat there is a sealing engagement between the flared plug 57 and checkpiston 54 so as to preclude the free passage of fluid through passages63 in flared plug 57.

An annular channel for receiving a low pressure seal 68 is formed incentral bore 50 immediately below annular shoulder 47. Low pressure seal68 cooperates with the outer surface of check piston 54 to preclude thepassage of low pressure fluid upwardly around check piston 54 intochamber 66.

Connector 41 is provided on its upper end with a conically taperedsurface 70 which extends radially inwardly and upwardly from thethreaded surface thereof to a reduced diameter portion 71. Taperedsurface 70 and the reduced diameter portion 71 of connector 41 cooperatewith bore 34 in body 32 to define an annular channel for receiving ahigh pressure seal 72 (FIG. 3) comprising a soft O-ring seal and atapered antiextrusion ring which may be of any known suitable materialsuch as beryllium copper.

Spaced axially above high pressure seal 72 by a cylindrical spacerelement 74 is another high pressure seal 76 which comprises a softU-shaped seal and a tapered antiextrusion ring. As will be recognized bythose skilled in the art, the soft seal of high pressure seal 76 isU-shaped as distinguished from the soft O-ring seal of high pressureseal 72 in that high pressure seal 76 is subject to the reciprocation ofcheck piston 54 therethrough while under load, which reciprocation isbetter accommodated by a U-shaped soft seal than by an O-ring soft seal.The tapered surface of the antiextrusion ring of high pressure seal 76bears against the lower generally radially extending surface of annularshoulder 48, which surface is provided with a taper which complementsthat of the antiextrusion ring.

As can be seen from FIG. 2, therefore, when valve 30 is aligned for highvolume low pressure flow, passage of fluid upwardly around check piston54 is prevented by low pressure seal 68, passage of fluid downwardlyaround connector 41 is prevented by high pressure seal 72 (FIG. 3), andpassage of fluid upwardly through bore 55 of check piston 54 isprevented by the firm seating of surface 58 (HO. 2) of plug 57 againstthe tapered surface 61 of check piston 54.

In the same manner as described above with respect to connector 41, highpressure connector plug 37 is provided with a tapered surface 78 whichextends radially inwardly and downwardly from the threaded surface ofplug 37 to a reduced diameter portion 79 formed on the lower end of plug37.

Tapered surface 78 and the reduced diameter portion 79 of plug 37cooperate with bore 34 in body 32 to define an annular channel forreceiving a high pressure seal 82 comprising a soft O-ring seal and atapered antiextrusion ring. High pressure seal 82 is retained inposition by a spring ring 83 which is mounted in a suitable annularchannel formed in the reduced diameter portion 79 of plug 37.

The upper surface of radial shoulder 64 of check piston 54 is providedwith a taper for receiving, in surface-to-surface engagement, thetapered surface of the antiextrusion ring of a high pressure seal 85,which'also includes a U-shaped soft seal of the type used in highpressure seal 76. Seal 85 is secured in position by a spring ring 86mounted in a suitable annular channel formed in the outer surface ofcheck piston 54.

Between high pressure seal 82 and high pressure seal 85 there isprovided an additional O-ring 88 which maybe made of any resilientmaterial. O-ring 88 acts as a shock absorber between the two highpressure seals to soften the impact of check piston 54 rising from thelower volume, high pressure flow position of FIG. 3 to the high volume,low pressure flow position of FIG. 2.

Referring to FIG. 3, it can be seen that check piston 54 is in itslowermost position thus aligning valve 30 for low volume high pressureflow. In this configuration, the high pressure fluid which is introducedthrough first inlet port 38 of connector plug 37 into the bore 34 ofvalve body 32, is prevented from passing out of the valve aroundconnector plug 37 by high pressure seal 82. Similarly, the leakage ofhigh pressure fluid around the radial shoulder 64 of check piston 54 isprevented by high pressure seal 85. Thus, high pressure fluid passesinto valve 30 through first inlet port 38, through bore 34 of body 32into and through bore 55 of check piston 54. Thereafter the highpressure fluid passes through passages 63 in plug 57 into the bore ofconnector 41 for further passage to a machine to be served, It can beseen that during the flow of high pressure fluid through valve 30,cylindrical spacer element 74 is exposed to the high pressure fluid andthat the leakage of high pressure fluid upwardly past check piston 54 ordownwardly past connector 41 is prevented by high pressure seals 76 and72 respectively. Thus, the entire path of high pressure fluid throughvalve 30 is sealed against leakage either out of the valve or into thelow pressure fluid system through radial passage 52.

Considering now the operation of dual pressure range valve 30 inconjunction with a machine to be served 44, which may be the punch pressII of FIG. I, valve 30 is initially secure to suitable sources of highand low pressure fluid and to the machine to be served 44. Thereafter, ahigh volume flow of low pressure fluid is introduced into valve 30through second inlet port 53 whereafter it passes downwardly throughbore 34 in body 32 and outlet port 42 in connector 41 into the machine44 to be served. If machine 44 is a punch press such as punch press IIof FIG. I, sufficient low pressure fluid will be provided to displacepiston I4, and therewith punching ram 112 from the retracted positionshown in FIG. Ia to the position (not shown) in which punching ram I2 isin surface-to-surface contact with blank I7, i.e. through a distance xas shown in FIG. Ia.

When the high volume of low pressure fluid passing through valve 30 hasaccomplished its function, e.g. the downward displacement of piston I4,high pressure fluid is introduced to valve 30 has accomplished itsfunction, e,g, the downward displacement of piston I4, high pressurefluid is introduced to valve 30 through first inlet port 38 in highpressure connector plug 37 from a high pressure fluid source (notshown). The force of the high pressure fluid displaces check piston 54and therewith check stem 56 downwardly from the position shown in FIG. 2to the position shown in FIG. 3. More specifically, check piston 54 isdisplaced downwardly until the lower surface of radial shoulder 64 abutsthe upper surface of annular shoulder 47. Check stem 56 is displaceddownwardly until the lower conical surface 59 of flared plug 57 seats onthe tapered surface 62 of connector 41. With the check piston 54 andcheck stem 56 in these positions, the upper conical surface 58 of flaredplug 57 is axially displaced from the tapered surface 61 in the lowerend of check piston 54 so as to allow the free passage of high pressurefluid therebetween.

With the dual pressure range valve aligned as shown in FIG. 3,therefore, high pressure fluid passes into the valve through first inletport 38 in plug 37, into bore 34and through bore 55 in check piston 54,through passages 63 in plug 57 and out of valve 30 into the machine tobe served 44 through outlet port 42 in connector plug 41.

If the machine to be served is the punch press II of FIG. I, sufficienthigh pressure fluid is provided to displace piston I4 and advancepunching ram I2 through the distance y as shown in FIG. 1b so as tocause the punching ram I2 to penetrate the blank 17 and punch out a discI6 therefrom. Upon completion of the high pressure punching operation,low pressure fluid is introduced to the underside of piston I4 throughlow pressure fluid line 24. The high pressure then being relieved in thefluid above piston I4, the pistonand therewith the punching ram iscaused to retract, i.e. to be displaced upwardly through a distance zFIG. 1c, from the position shown in FIG. Ib to that shown in FIG. 10. Ifthe valve I0 in use with punch press II during the retraction of pistonI4 is a dual pressure range valve 30 structured in accordance with theteaching of the present invention, the flow of fluid from the machinebeing served back through outlet port 42 in connector 41 causes checkstem 56 to be displaced upwardly against check piston 54 so as to sealbore 55 against the passage of fluid therethrough. Thereafter, checkstem 56 and check piston 54 are displaced upwardly together from theposition shown in FIG. I to the position shown in FIG. 2 so as touncover radial passage 52 to allow passage of the fluid from valve 30,through second inlet port '53 back into the low-pressure fluid system.With check piston 54 now in the upward position, valve 30 is again inproper alignment for commencing another cycle of the machine to beserved.

Referring now to FIG. 4, there is shown another embodi-. ment of a dualpressure range valve structured in accordancewith the present inventionand designated generally by the reference numeral I30. Valve I30 issubstantially exactly the sameas valve 30 of FIGS. 2 and 3 with threeexceptions: first, valve I30 utilizes a ball check valve structure inplace of the stem check valve structure used with the check piston 54 ofvalve 30; there is no low pressure seal to preclude the passage of lowpressure fluid upwardly around the check piston of valve I30, intochamber I65; and, there is no provision for venting the bore of valveI30, which venting is accomplished by vent passage 65 of valve 30.

Considering the structure of valve in greater detail, it can be seen tocomprise a body I32 having a bore I34 extending longitudinally axiallytherethrough. One end of bore I34, the upper end as seen in FIG. 4 isprovided with a threaded counterbore I36 for receiving a high pressureconnector plug I37. Connector plug I37 is provided with an axiallyextending bore to define a first inlet port 138 through which highpressure fluid is introduced to valve I30 from a suitable source (notshown). The other end of bore I34, the lower end as seen in FIG. 4, isprovided with a threaded counterbore I 30 which is for threadedlyreceiving a connector I4I. Connector I4! is provided with alongitudinally axially extending bore to define an outlet port I42 foraccommodating the passage of high or low pressure fluids from valve I30.Connector MI may be secured directly to the inlet orifice I43 of amachine I44 to be served, e.g. the punch press II of FIG. I or it may besecured to a suitable high pressure fluid line (not shown).

A pair of axially spaced, radially inwardly extending annular shouIdersI47, I40 are formed on the inner surface of bore I34. Shoulders I47, I43cooperate to define a central bore portion I50 from which a passage I52extends radially through valve body I32. The outer end of passage I52defines a second inlet port 153 to valve I30, and is provided withthreads for accommodating the connection thereto of a suitable source ofa high volume, low pressure fluid (not shown).

Slidably mounted within bore 134 is a check piston 154 having a bore 155extending longitudinally axially therethrough. Bore 155 is provided atits upper end with a counterbore 156, the top portion of which isthreaded and the bottom portion of which is provided with a plurality ofradially oriented tapered slots 157 for communicating counterbore 156with bore 155 as is discussed below. Threadedly received in the upperend of counterbore 156 is a flange 158, the major diameter of which issubstantially equal to the diameter of bore 134. Flange 158 is providedwith an axially extending bore 159 therethrough which cooperates withcounterbore 156 to define a cage for containing a ball check 160. Ballcheck 160 is of a diameter greater than bore 159 but less than thediameter of counterbore 156 and is normally urged upwardly by the biasof a spring 161 mounted in counterbore 156 below ball check 160. Thisbeing the case, ball check 160 when positioned in its uppermost positionas shown in FIG. 4 in solid lines, precludes the passage of fluidupwardly through bores 155 and 156 into bore 159. When ball check 160 isdisplaced downwardly against the bias of spring 161 to its lowerposition, (e.g., to a position located in the lower part of thecounterbore 156) fluid is free to pass from bore 159 and throughcounterborc 156 into bore 155 through slots 157. Thus, ball check 160defines a check valve which permits the passage of high pressure fluidthrough valve 130 to a machine to be served 144, and prevents thepassage of fluid out of valve 130 through port 138 when high pressure isnot being exerted thereon through port 138.

Formed adjacent the upper end of check piston 154 is a radiallyoutwardly extending shoulder 164. The diameter of shoulder 164 issubstantially equal to the diameter of bore 134 so as to provide asurface-to-surface sliding fit therebetween. The outer surface of checkpiston 154, bore 134, the lower surface of shoulder 164 and the uppersurface of shoulder 147 cooperate to define a chamber 165.

In similar manner to that described above with respect to valve 311, aplurality of high pressure seals 172, 182 and 185 are provided in valve1311 to preclude the leakage of fluid from the valve around connector141, high pressure connector plug 137 and radial shoulder 164respectively. Each of these seals comprises a soft U-shaped seal and anantiextrusion ring as was discussed above with respect to seals 76 and85 of valve 30. It is to be noted that distinguishably from valve 30 ofFIG. 2 and 3, no low pressure seal is provided in central bore 151) ofvalve 130 adjacent annular shoulder 147 to prevent passage of fluid pastshoulder 147 into chamber 165. Further, it is to be noted for reasonsdiscussed below, that chamber 165 is not vented as is the case in valve31).

As shown in FIG. 4, check piston 154 is in its uppermost position and istherefore aligned for high volume low pressure fluid flow. Morespecifically, during high volume low pressure flow, low pressure fluidis introduced to valve 130 through second inlet port 153 whereafter ittravels through radial passage 152, central bore 150 and outlet port 142into a machine to be served 144, e.g. the punch press 11 of FIG. 1. Lowpressure fluid also passes upwardly within bore 155 in check piston 154to urge ball check 160 upwardly against flange 158 so as to cover bore159 to preclude the passage of fluid therethrough. Additionally, lowpressure fluid passes between the outer surface of check piston 154 andthe inner surface of annular shoulder 147 into chamber-165 so as to bearagainst the lower surface of radial shoulder 164 and maintain checkpiston 154 in its uppermost position.

When the cycle of the machine is to be served requires the introductionof high pressure fluid thereto, high pressure fluid highpressure fluidout of valve through radial passage I52 and second inlet port 153.During the downward displacement of check piston 154, ball check is heldseated against bore 159 by the action of spring 161. When check piston154 has reached the limit of its downward displacement, however, ie whencheck piston 154 engages the upper surface of connector 141, ball check160 displaced downwardly against the bias of spring 161, to seatagainst,'without covering, slots 157. With the ball check so positioned,high pressure fluid passes through first inlet port 138 into bore 159,through counterbore 156, slots 157, and bore 155, and thereafter out ofvalve 130 through bore 152 in connector 141.

When the high pressure fluid-requiring function of machine 144 has beenaccomplished, the pressure from the high pres sure fluid source isrelieved and check piston 154 is displaced upwardly into high volume lowpressure alignment as shown in FIG. 4 in either of two ways, viz by theaction of fluid being passed into valve 130 through bore 142 as was thecase with respect to valve 30 in use with the punch press 11 of FIG. 1,or by the introduction of additional low pressure fluid through secondinlet port 153 into valve 130. In the latter case, the upwarddisplacement of check piston 154 is caused by the passage of lowpressure fluid between the outer surface of check piston 154 and theinner surface of annular shoulder 147 into chamber so as to bear againstthe lower surface of radial shoulder 164 thereby causing upwarddisplacement of check piston 154. This capability for self-realignmentis particularly useful for situations where valve 130 is to be used inconjunction with machinery having requirements for a high volume of lowpressure followed by a requirement for a low volume of high pressure,immediately followed by a further requirement for a high volume of lowpressure without an intermediate phase wherein an element of themachine, e.g. piston 14 of punch press 11 of FIG. 1, is repositioned.

It will be understood by those skilled in the art that theabove-described embodiments of dual pressure range valves may bemanufactured by known processes and that they are representative of manydual pressure range valves which may be structured in accordance withthe teaching of the present invention. Manifestly, many modificationsand adaptations may be made in the present invention without departingfrom the spirit and the scope thereof.

lclaim:

1. A dual pressure range valve comprising:

an elongated body having a first bore extending axially therethrough;

a first inlet port formed at one end of said first bore foraccommodating the introduction of fluid at a first pressure into saidfirst bore of said body;

an outlet port formed at the opposite end of said first bore foraccommodating the discharge of fluid therethrough from said first boreof said body, said outlet port tapered conically outward toward theperiphery of said first bore at its innermost end section;

said body having a second bore extending transversely therein one end ofsaid second bore intersecting said first bore so as to communicatetherewith;

second inlet port formed at the other end of said second bore foraccommodating the introduction of fluid at a second pressure into saidfirst bore of said body;

a pair of longitudinally displaced radially inwardly extending annularshoulders formed on said first bore of said body, said second borecommunicating with said first bore at a point between said pair ofannular shoulders;

an elongated reciprocable check piston slidably mounted for axialmovement within said pair of shoulders of said first bore to alternatelyopen and close said communication between said second bore and saidfirst bore during the passage of fluid through said first bore, saidpiston having affixed thereto an outward extending annular sleevesituated externally of the outermost of said pair of shoulders on saidfirst bore and engageable therewith to limit said axial movement of saidpiston having a longitu- 9 dinal bore therethrough, said bore of saidpiston tapered conically outward at its innermost end section; and

an elongated stem-check valve mounted within said bore of said pistonduring the reciprocal movement of said piston so that said first conicalsurface of said plug movably engages adjacent conical surface of saidbore of said piston to preclude fluid passage from said first inlet portto said outlet port when said piston opens said communication betweensaid second bore and said first bore. and said second conical surface ofsaid plug is alternately movably engages with said adjacent conicalsurface of said outlet port to permit fluid passage from said firstinlet port to said outlet port when said piston closes saidcommunication between said second bore and said first bore.

1. A dual pressure range valve comprising: an elongated body having afirst bore extending axially therethrough; a first inlet port formed atone end of said first bore for accommodating the introduction of fluidat a first pressure into said first bore of said body; an outlet portformed at the opposite end of said first bore for accommodating thedischarge of fluid therethrough from said first bore of said body, saidoutlet port tapered conically outward toward the periphery of said firstbore at its innermost end section; said body having a second boreextending transversely therein one end of said second bore intersectingsaid first bore so as to communicate therewith; second inlet port formedat the other end of said second bore for accommodating the introductionof fluid at a second pressure into said first bore of said body; a pairof longitudinally displaced radially inwardly extending annularshoulders formed on said first bore of said body, said second borecommunicating with said first bore at a point between said pair ofannular shoulders; an elongated reciprocable check piston slidablymounted for axial movement within said pair of shoulders of said firstbore to alternately open and close said communication between saidsecond bore and said first bore during the passage of fluid through saidfirst bore, said piston having affixed thereto an outward extendingannular sleeve situated externally of the outermost of said pair ofshoulders on said first bore and engageable therewith to limit saidaxial movement of said piston having a longitudinal bore therethrough,said bore of said piston tapered conically outward at its innermost endsection; and an elongated stem-check valve mounted within said bore ofsaid piston, said stem check having a flared plug at its innermost endwhich protrudes from said bore of said piston, said plug having a firstcomplementary conical surface adjacent said conical surface of said boreof said piston, a second complementary conical surface adjacent saidconical surface of said outlet port, and a plurality of passagesextending from said first conical surface through a third surface ofsaid plug adjacent the bore in said outlet port, said stem checkreciprocable within said bore of said piston during the reciprocalmovement of said piston so that sAid first conical surface of said plugmovably engages adjacent conical surface of said bore of said piston topreclude fluid passage from said first inlet port to said outlet portwhen said piston opens said communication between said second bore andsaid first bore, and said second conical surface of said plug isalternately movably engages with said adjacent conical surface of saidoutlet port to permit fluid passage from said first inlet port to saidoutlet port when said piston closes said communication between saidsecond bore and said first bore.